Lane County lies in between the Oregon Coast and the Northern
Cascade Mountain Range. It is within both Climate Division 1 (Oregon
Coast), Climate Diviation 2 (Willamette Valley) and Climate Division
(Northern Cascade) established by the National Climatic Data Center.
Below is a description of the climate of Division 1, 2 and 4 followed
by specific descriptions of Lane County. Climate tables for various parameters,
as observed at long-term climate stations in Lane County, are included
below

Climate Division 1 — Oregon Coast

Stretching along Oregon's Pacific border, the coastal zone is characterized
by wet winters, relatively dry summers, and mild temperatures throughout
the year. Coastal terrain features include a coastal plain (extending
from less than a mile to a few tens of miles in width), numerous coastal
valleys, and the Coast Range, whose peaks range from 2,000 to 5,500 feet
above sea level and extend down the full length of the state. Rivers
such as the Coquille, Umpqua, and Yaquina dissect the Coast Range and
drain its slopes. The area's heavy precipitation results from moist air
masses moving off the Pacific Ocean onto land, especially during winter
months. The abundant moisture supports lush pastures for dairy and animal
production as well as valley crops of grass seed, flower bulbs, nuts,
and fruit.

Along the lower elevations of the immediate coast, normal annual precipitation
is between 65 to 90 inches. However, spots high on the west slopes of
the range may get up to 200 inches. Several days of abundant rainfall
can cause strong flood events. In some locations, flood control dams
have greatly reduced the incidence of damaging floods. As is typical
of western Oregon, the highest monthly precipitation values for the coast
occur in the winter months of November, December, and January. Table
1 is a summary of mean monthly and annual precipitation for recording
stations in the coastal zone. Figure
1 shows NOAA climate stations in Zone 1, which were in operation
during the 1961-1990 period. Figure
2 shows the Lane County region
from the Oregon annual precipitation map. Table 2a and 2b lists
the average number of days with precipitation amounts exceeding certain
thresholds.

Snowfall' in tcoastal vicinity is minimal, usually only one to three
inches. Some of the higher elevations receive significant amounts of
snowfall, however. For example, in January of 1982, Laurel Mountain (elevation
3,589') received 55 inches of snow. At Mary's Peak (elevation 4,097'),
the highest peak in the Coast Range, snow often lasts into May. Table
4 lists average monthly and annual snowfall totals for various stations.

The months of July, August, and September tend to be the warmest, but
average summer temperatures are only about 15 degrees above the coldest
month, January.

Table 3 lists normal monthly temperature at stations
in the area. Average heating and cooling degree days (base 65 deg F)
are lower for the coastal region than any other Oregon region as a result
of the mild temperatures.

Extremely high or low temperatures are rare, and the annual temperature
range is lower than any other Oregon climate zone. Temperatures of 90
deg F or above occur, on the average, less than once per year, and freezing
temperatures are infrequent. Newport, for example, records temperatures
of 32 deg F or below an average of 30 times per year. Killing frosts
are even less frequent. Most of the area averages more than 300 days
between the last occurrence (in spring) and the first occurrence (in
fall) of 28 deg F temperatures. Table 5 and 6 list
median frost dates and mean growing seasons, respectively, for four different
temperature thresholds.

Occasional strong winds strike the Oregon Coast, usually in advance
of winter storms. Wind speeds can exceed hurricane force, and in rare
cases have caused significant damage to structures or vegetation. Damage
is most likely at exposed coastal locations, but it may extend into inland
valleys as well. Such events are typically short-lived, lasting less
than one day.

Skies are likely to be cloudy during winter, and only partly cloudy
during summer. At Astoria, average winter cloud cover is over 80 percent,
dropping only to about 65 percent in summer. Summer cloud cover is due
mostly to fog and low clouds. As a result of the persistent cloudiness,
total solar radiation is lower here than in any other part of the state.

The Willamette Valley is the most diverse agricultural area in the state
of Oregon, and also the home of the majority of the population. Oregon's
three largest cities, Portland, Salem, and Eugene, are located in the
north, central, and south portions of the Valley, respectively. The urban
areas are surrounded by varied and productive ranches, orchards, and
farms. Among the crops grown in significant quantities are tree fruits,
nuts, berries, mint, grains, and hay. Livestock operations are also common,
including the dairy and poultry industries.

The climate of the Valley is relatively mild throughout the year, characterized
by cool, wet winters and warm, dry summers. The climatic conditions closely
resemble the Mediterranean climates, which occur in California, although
Oregon's winters are somewhat wetter and cooler. Growing seasons in the
Willamette Valley are long, and moisture is abundant during most of the
year (although summer irrigation is common).

Like the remainder of western Oregon, the Valley has a predominant
winter rainfall climate. Typical distribution of precipitation includes
about 50 percent of the annual total from December through February,
lesser amounts in the spring and fall, and very little during summer.
Rainfall tends to vary inversely with temperatures -- the cooler months
are the wettest, the warm summer months the driest. Figure
1 shows NOAA climate stations in Zone 1, which were in operation
during the 1961-1990 period. Figure
2 shows the Lane County region
from the Oregon annual precipitation map.

There is considerable variation in precipitation in the Valley, ranging
from annual totals below 40 inches in the Portland area to upwards of
80 inches in the Cascade and Coast Range foothills. Elevation is the
single most important determinant of precipitation totals. Table
1 shows a plot of monthly & annual average precipitation versus
elevation for stations in the Valley, and indicates a strong correlation
between the two. Even in the lower sections of the Valley the effects
of elevation are pronounced. Portland, for example, at 21 feet above
sea level, receives an average of 37.4 inches (30-year normal), while
Salem (196 feet) receives 40.4 inches and Eugene (359 feet) receives
46.0 inches. Thus, a change of only 338 feet of elevation produces an
increase of 23 percent above Portland's total. Table
2a and 2b list the average number of days
with precipitation amounts exceeding certain thresholds.

Table 3 lists normal monthly temperature at stations
in the area. Extreme temperatures in the Valley are rare. Days with maximum
temperature above 90 deg F occur only 5-15 times per year on average,
and below zero temperatures occur only about once every 25 years. Mean
high temperatures range from the low 80's in the summer to about 40 deg
F in the coldest months, while average lows are generally in the low
50's in summer and low 30's in winter. The mean growing season (days
between 32 deg F temperatures) is 150-180 days in the lower portions
of the Valley, and 110-130 days in the foothills (above about 800 feet). Table
6 lists the mean growing season for Zone 2.

Although snow falls nearly every year, amounts are generally quite
low. Valley floor locations average 5-10 inches per year, mostly during
December through February, although higher totals are observed at greater
elevations in the foothills. Table 4 lists average
monthly and annual snowfall totals for various stations.

Table 5 lists the median frost dates for Zone
2. Severe storms are rare in the Valley. Ice storms occasionally occur
in the northern portions of the Valley, resulting from cold air flowing
westward through the Columbia Gorge. High winds occur several times per
year in association with major weather systems.

Relative humidity is highest during early morning hours,
and is generally 80-100 percent throughout the year. Humidity is generally
lowest during
the afternoon, ranging from 70-80 percent during January to 30-50 percent
during summer. Annual pan evaporation is about 40 inches, mostly occurring
during the period April - October.

Winters are likely to be cloudy. Average cloud cover during the coldest
months exceeds 80 percent, with an average of about 26 cloudy days in
January (in addition to 3 partly cloudy and 2 clear days). During summer,
however, sunshine is much more abundant, with average cloud cover less
than 40 percent; more than half of the days in July are clear.

The Cascade Mountains, the dominant terrain feature in Oregon, encompass
the entire length of the state from the California border to Washington.
With average elevations in excess of 4,000 feet, the Cascades are crowned
with a number of very high peaks. Mount Hood, near the Washington border,
exceeds 11,000 feet, while Mt. Jefferson and the Three Sisters exceed
10,000 feet. Mt. McLoughlin near Medford is approximately 9,500 feet.
The Cascades are a higher and more imposing topographic feature in the
northern part of Oregon, however. Average elevations and the number of
tall peaks (over 9,000 feet) are higher north of about 43.5 deg N latitude.
The region extending northward from this latitude to the Columbia River
and encompassing high elevations west of the Cascade crest is the fourth
of nine Oregon climatic zones.

The northern Cascades exert a profound effect on Oregon climate and
weather. Mid-latitude storms approaching from the west are forced to
rise as they encounter the Cascades, resulting in large amounts of orographic
(terrain-induced) precipitation on the western slopes. So effective are
the Cascades in removing moisture from the Pacific air masses, however,
that most of Oregon east of the Cascades lies in a "rain shadow," resulting
in large areas with annual precipitation less than 12 inches. Most of
the northern Cascades, on the other hand, receive an excess of 80 inches
per year; the highest peaks collect more than 150 inches per year, most
of it in the form of snow. As in the case of rest of western Oregon,
most of the precipitation in the Northern Cascades falls during the winter
months with November through March period accounting for more than 75
percent of the total annual precipitation. Spring and fall rain and snow
and summer thunderstorms contribute to the annual precipitation total,
but they are dwarfed by the winter precipitation totals. Table
1 lists monthly and annual normal precipitation at Zone 4 sites.

Tables 2a and 2b list
the average number of days with precipitation amounts exceeding certain
thresholds.

Table 4 lists average monthly and annual snowfall
totals for various stations. Monthly mean snowfall totals vary significantly
according to elevation. Since precipitation tends to increase with increasing
elevation, more potential moisture for snowfall is available at higher
elevations. Since temperatures generally decrease with increasing elevation,
those high precipitation amounts are more likely to be in the form of
snow. As an example, McKenzie Bridge (elevation 1400 feet) receives an
average of about 42 inches snow per year, while Marion Forks (2,500 feet)
receives about 150 inches and Government Camp (3,980 feet) about 300
inches per year. Figure
1 shows NOAA climate stations in Zone 4, which were in operation
during the 1961-1990 period. Figure
2 shows the Lane County region
from the Oregon annual precipitation map.

Table 3 lists normal monthly temperature at stations
in the area. The correlation of temperature with elevation is quite strong,
with the highest station (Government Camp) having consistently lower
temperatures than the other sites. McKenzie Bridge has by far the highest
annual mean maximum temperatures, but its annual average temperature
is only slightly higher than Detroit Dam due to lower minimum temperatures
at McKenzie.

Table 5 and 6 list median
frost dates and mean growing seasons, respectively, for four different
temperature thresholds. Detroit Dam, at an elevation of 1,220 feet, has
an exceptionally long growing season. This is probably due to the fact
that its location above the valley floor prevents significant accumulation
of cold air on clear nights, and the presence of nearby Detroit Lake
serves to moderate any low temperatures. The growing season at higher
elevation sites such as McKenzie Bridge, Marion Forks, and Belknap Springs
is only about 50 percent as long as at Detroit: for example, Marion Forks
at 2,480 feet has an average of only 116 days between occurrences of
32deg F temperatures compared with 244 days at Detroit Dam.

Lane County was named for Gen. Joseph Lane, a rugged frontier hero who
was Oregon's first territorial governor. Pioneers traveling the Oregon
Trail in the late 1840s came to Lane County mainly to farm. The county's
first district court met under a large oak tree until a clerk's office
could be built in 1852. A few years later, the first courthouse opened
in what is now downtown Eugene. With the building of the railroads, the
market for timber opened in the 1880s. Today, wood products are still
an important part of the economy in addition to high-tech manufacturing
and tourism. Lane County government operates under a home rule charter
approved by voters in 1962. Although 90 percent of Lane County is forestland,
Eugene and Springfield comprise the second largest urban area in Oregon.